
final class Demo {
    public int a;
    public int b;
}
//class Demo2 extends demo {
//
//}
public class Main {
    public static void main(String[] args) {
//        final int x = 10;
//        x = 20;//x报错
//        System.out.println(x);

//        final int[] array = {1,2,3,4};
//        array = new int[10];//array报错
//        array[0] = 99;
    }
}